Catastrophe Theory and Other Things
by DearSweetPapercut
Summary: "Greg perked up slightly realising how interesting studying with Sara could be..."


Set post 'Doom and Gloom'.

I've been sad about the lacking of Sara/Greg on the show recently.

Please review!

Disclaimer: I own zilch.

**Catastrophe Theory and Other Things **

"Okay...we're on to Catastrophe Theory..." Sara smiled her eyes focused on the book that was resting against her knees as she sat with her feet on Greg's lap.

"Uhm...Originally the work of René Thom in the 1960s" he began a slightly bored sigh. "It's a branch of bifurcation theory which classifies the phenomena of sudden shifts in behaviour arising from small changes in circumstances."

"Good boy..." She responded teasingly. "But you're going to have to keep going if you want full marks..."

"Can we take a break...I'm bored." Greg groaned leaning his head back, pouting slightly at his friend.

"Wait here..." Sara smirked climbing on to her feet disappearing in the direction of the kitchen. It was a few minutes before she re-appeared with a bottle of tequila and shot glasses a devilish smile playing on her lips.

"So...here is how it goes." She smiled kneeling by the coffee table placing the bottle down. "We'll do shots for every question- every question you get right I'll remove an item of clothing...every question you get wrong...you take off an item of clothing."

"How long have you waited for this day Sara?" Greg asked in a low voice, smirking slightly.

"I wouldn't have offered if I didn't think you'd be the one getting naked here Greg..." She gave him a half smile filling the shot glasses up.

"Oohhh...harsh words Ms Sidle..." He laughed sitting down cross legged on the floor opposite her.

"Okay...question one...What is 'Proof Theory'?" She asked her eyes on the book on the floor beside her.

"It is...mathematical logic...represent proofs as formal mathematical objects in order to facilitate their analysis." Greg beamed knowing that he had gotten the answer right.

"Well done." Sara nodded removing her sweater revealing the plain black t-shirt she was wearing underneath. She took the shot with one swift motion and indicated for him to take his. Greg perked up slightly realising how interesting studying with Sara could be...

"Next question...What are most three best known proof calculi?" She asked topping up the shot glasses while Greg thought about his answer.

"Hilbert Calculi...natural deduction calculi and...sequent calculi" Greg answered slowly, hoping he had identified the correct answers.

"Correct." Sara took her shot removing her watch and placing it on the table with a sly smile.

"That doesn't count as an item of clothing..." Greg protested, slightly disappointed that her shirt hadn't been the next to go.

"I was wearing it...was I not?" She raised an eyes brow. "What are topological spaces?"

"There are structures that define concepts." He said flippantly.

"Uh-uh." Sara smirked. "They are structures that allow the definition of concepts- they don't define concepts themselves. They are merely facilitators."

"Semantics..." he grumbled.

"But if I were the examiner...I wouldn't give you the mark...because technically that's incorrect." She shrugged after giving him a sympathetic look.

"Fine..." Greg removed his watch and placed it down beside Sara's before crossing his arms across his chest leaning against the sofa.

"Which theory involves approximating functions with simpler functions?" Sara asked pursing her lips.

"Approximation theory" Greg seemed assured.

"Correct" They took their next shots and this time Sara removed the necklace she was wearing. Greg gritted his teeth slightly realising that this was going to be a long night.

"What is the floating point?" She was clearly getting bored too and in that moment he realised that he had the upper hand he knew he could distract her.

"I don't care..." Greg rolled his eyes.

"That...is not the right answer." Sara smiled sweetly at him before taking her shot. Greg stood up making a show of undoing every button on his shirt as slowly as he could before he removed it tossing it aside. Sara's eyes seemed to be glued to his body running from his shoulders down to the waistband of his trousers taking in the muscles, freckles and scars.

"Like what you see?" Greg smirked realising that his plan had worked- Sara was distracted enough that with a few more questions she'll forget why she was there in the first place.

"Er...no...What type of graphs is Braid Theory associated with?" She asked attempting to keep her eyes focused on the text book.

"Planar Graphs" Greg replied enjoying watching Sara's slightly agitated behaviour.

"Correct" She took her shot and pulled her t-shirt over her head exposing the black silk bra. "Like what _you_ see?" She asked Greg with a slightly wicked smile.

"I've seen better" he shrugged attempting to not let show that his heart rate had just doubled as he imagined putting his hands on her.

"Your porn collection shouldn't count..." Sara gave a low gravely laugh. "What type of theory is Braid Theory?"

"Abstract geometric theory" Greg replied. Sara pursed her lips clambering on to her feet, the eight shots of tequila beginning to take clear effect as she did so. She undid her jeans, shimming out of them revealing matching black panties.

"I don't remember math ever being this much fun at school..." Greg commented his eyes washing over her long legs as she collapsed into the sofa behind her.

"I do..." Sara gave another throaty laugh sending a shiver down Greg's spine. "I dated my college Math professor..."

"I bet you were the only one who paid any attention." Greg mused that the bit of information she had revealed.

"Well...you should pay attention to me...you could learn a thing or two..." Sara muttered closing her eyes and arching her back against the sofa stifling a yawn.

"You got that right." Greg murmured he eyes following the curve of her body attempting to push all the filthy thoughts that had come into his mind aside.

"What does string theory a model for?" Sara asked keeping her eyes shut as she leant back against the sofa taking the shot before Greg had bothered answering the question.

"Model that describes all fundamental forces and forms of matter" Greg answered anticipating the next item of clothing Sara would remove.

"What do you want next?" She intensely met his gaze as she placed her hands on the coffee table move her body towards him.

"You..." He responded without hesitation.

There was a moment's silence and the room seemed to still as neither one of them knew how they were going to respond to what had just been said. Greg leant forwards on the table his hands placed opposite Sara's and without a word he placed his lips on hers. The kiss began slowly and nervously but suddenly stopped as they realised what they were doing.

Sara made the short walk around the coffee table standing in front of Greg she pulled him towards her kissing him again but this time with more passion. She pushed at Greg's shoulders so he was sitting on the sofa and climbed onto this lap with their lips still connected. He flipped her onto her back eliciting a gasp from Sara as his lips trailed down her neck, her legs firmly wrapped around his waist. Sara arched her back allowing him to undo her bra, Greg removed it and threw it onto the floor kissing the skin it had exposed, glancing up to see her expression as he paused in between her breasts.

The anticipation was almost impossible to mask as he breathing became slowly more erratic. Greg kissed and massaged her breasts as she withered below him, her hands tangled in his hair pulling him closer to her body. He slithered down her torso his hands smoothing over her thighs before he grasped the silky fabric of her panties in his hand ridding of the barrier as quickly as he could.

Sara gasped at the feeling of his tongue moving against her as he hooked her legs over his shoulders providing him with better access. His hands ran slowly past her hips and stomach before his finger tips slowly dusted over her breasts. His touch became more deliberate as he sped up his pace- Sara's hands gripped the sofa gasping at the change. Greg pinched her nipples pressing his tongue hard against her clit a small scream escaping Sara's lips as she felt her body tighten. She fell back against the sofa again breathing heavily as her body recovered from the shivers that rippled from her core.

Greg pulled back removing his trousers and boxers as he did so, his legs straight ahead of him. Sara pulled herself up hovering over him on her hands and knees. She lowered herself onto him, curling her feet around his thighs, Greg growled at the feeling of being inside her. Sara bit her lip to stop herself from moaning as she gripped onto the armrest of the sofa. She began moving in small circles rotating her hips against him, slowly speeding up her pace as could feel herself growing steadily tighter. Sara eventually stilled over him a loud moan escaping her lips as she felt her muscles clench around him. Greg soon followed releasing himself inside her with a satisfied sigh.

She clambered into the space beside him resting her head on his shoulder her letting her breathing slow down. He absentmindedly rubbed her back his body still throbbing from what they had just done.

"I should ask you to help me study more often..." Greg mused.

"I think you could learn a thing or two from me." Sara laughed into his skin, letting him bring her closer to him.

The air in the room lingered hot and heavy with the scent of their sex as the sound of the breathing collided like a symphony. They realised that in that evening they had both learnt catastrophe theory and many other things...

**The End **


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